It is often desirable in the natural gas, petrochemical and oil industries to withdraw samples directly from pipelines, vessels or process for analysis or measurement of the fluid. Various instruments are used for this purpose, such as calorimeters, gravitometers, and hydrogen sulfide analyzers. The pipeline can be taped and a sample drawn directly therefrom, however the pressure of the fluid in a pipeline is often too high for use in analyzing or measuring instruments. Pipelines carry natural gas at pressures as great as 5,000 pisg, while many gas analyzing instruments cannot use samples at greater than 100 psig. Regulators are used to step down pipeline pressures to instrument pressures. This reduction in pressure may also cause a drop in temperature due to the Joule-Thomson effect which can also cause condensation of gases. Condensation is undesirable for gas entering instrumentation systems.
Therefore, many regulators are heated to counter the Joule-Thomson effect and reduce the condensation of gas. For example, Welker Engineering Company, of Sugar Land, Tex., the assignee of the present application has sold a heated regulator described on a brochure included in the Information Disclosure Statement filed herewith and is the owner of U.S. Pat. No. 5,907,107, for a Heated Instrument Regulator Tip. Other companies, such as GO Regulator of Spartanburg, S.C. sell a variety of electrically heated and steam heated regulators, brochures of which are likewise included in the Information Disclosure Statement filed herewith. Some of the GO regulators have a spiral wrapped screen as the heat exchange surface. The problem with many of these prior art heated regulators is that they do a poor job of actually heating the gas. There is a need for improved heat exchange in regulators and other devices to prevent condensation of gases prior to entering instrumentation systems.